Engine Ops

In draft stages. Don’t read – not yet ready for viewing. 10/30/16

The ASG32 is a high performance state of the art glider, that also comes equipped with an engine.

The important factor for a motor glider pilot consider, first and foremost, is that the engine is only available for the purpose of making the retrieve more convenient. The engine is not something that will allow you to fly further away from a landable areas when the lift is so marginal that you may risk a landout. Rather than land somewhere, after losing the lift and getting too low, the motor glider pilot has the option of climbing back to a safe altitude and going back home, without having to land, wait for a retrieve vehicle to arrive. The folks at Schleicher have refined the words over the years, but the message has always been the same. Here is an extract from page 4.17 of the Schleicher Factory Flight Manual for the ASG32Mi :

………………………………………… The power plant of a poweredsailplane must not be regarded as a life insurance, for instancewhen crossing unlandable areas. One should always be prepared forthe possibility that the power plant will fail to deliver the hoped-for propulsion.This may not necessarily be due to a technical shortcoming, butmight be caused by nervous tension of the pilot (mistakes in carrying outstarting procedure).The engine and its reliability should be regarded in the same light asthat of a sailplane pilot not always finding a thermal when it is most urgentlyneeded. The engines of powered sailplanes are not subject toquite such stringent production and test regulations as normal aviationengines, and therefore cannot be expected to be quite as reliable.

A minimum safe height for extending the propeller and starting the enginemust be met. The criterion is that it must be possible to retract thepropeller again and carry out a normal sailplane out landing if the enginecannot be started. A general valid value for this minimum safe height isabout 300 meters (980 feet); however, this also depends strongly on pilotability and geographic factors.

I cannot overemphasize the importance of the above words. But for casting shame and embarrassment on others, I would mention names, places, and dates that are examples of reliable engines failing to start, several of which destroyed the motor glider. Don’t be one of the statistics. Before you perform the Inflight Engine Start Checklist you must identify the place you are going to land, and of course, you need to be within adjusted/ adequate glide distance of that field (assuming the propeller is extended but not operating). I have had the engine fail to start inflight on no less than three occasions, and on each occasion, I landed without incident – and on two of those instances the engine was extended. Granted that was over a period of 12 years, while accumulating over 1,000 hours of flying time on those two motor gliders, but it could happen tomorrow just as well.

Let’s not be afraid of the engine. It is an asset. It’s extremely valuable. The engine in this ship is the state of the art. Use it when ever you need it – just adhere to the cautions and procedures.

Let’s look at starting procedures. The Flight Manual says this in a portion of paragraph 4.5 (you need to read and understand the entire flight manual – do not rely on this extract!)

Here is my version of my engine start checklist and the engine shutdown (stop) checklist:

Engine Start

Change Over Switch – Front

Gear – Down (below 2,000 AGL)

Fuel – Open

Throttle – Idle (1/4 if on ground)

Speed 49 to 59 kts

ILEC – On

Extend Prop – Up (Green light)

Prop Stop – Off

Ignition – On

Fuel Pump 2 – Off

Starter – On (5 secs. max)

Warm – if possible – at 4,000 (3 – 4 Minutes)

Ignition Check – 6200 (drop 300 max)

Engine Stop

Cool it

Speed 49 to 59 kts

RPM – Stabilized at Idle

Ignition – Off

Prop Stop – On (after rotation stops)

Retract Prop – (hold to the beep)

Retract/Stow Prop – (after pulsing beeps)

ILEC – Off

From paragraph 2.5 (color added for affect)….

A extract from paragraph 4.5:

This is a fixed pitch prop. If throttle is held constant and you lower the nose to allow the airspeed to increase, then the RPMs will increase. You discover that if you want to fly a constant airspeed, then you need to control the RPM so they remain below your target RPM while you adjust the pitch and get the airspeed stabilized, and THEN, you adjust the throttle to achieve your desired RPMs. Definitely respect all RPM limits. Not doing so will destroy the engine.

Here is the graphic of the ECU in the flight manual (color added for clarity).

asdand here Photo just forward of the stick, in the front seat. Note the 15 Amp circuit breaker in the center of the throttle quadrant, along with a red release tab just below the breaker. This circuit breaker is called the “Power plant main switch”

In my ASH26E I routinely flew with this “switch” in the off or open position. While at the same time, I pre-positioned the prop extend switch to “Extend”

The result of this is that when it was time to start the engine in flight, I had completed the first five items in my start checklist earlier, and then I simply established the correct speed, reached down and made sure both handles (Throttle and Prop Brake) were all the way down as I closed that “switch”. The prop started to extend immediately. I see the green Prop retract light immediately go out and the center prop red light illuminate. As soon as I see the Green prop extend light illuminate, I unlock the prop and then hit the starter button. You can see the simplicity of the start, IF you perform parts of the checklist well in advance.

Not complicated – you just need to get familiar with procedures and the equipment.

Of course there is a lot more to the full spectrum of engine ops, so read the book and know the temp ranges and limits for Air and Water. Understand where the air temp is measured and the downside of flying slowly when the air temp is high. Know the cooling procedures. 100 degree days in the Sacramento Valley will give you a 100 degree temp at 4,000 feet and may lead to engine overheat. Learn the techniques needed to avoid hitting any temp limits.

Lots of subject areas related to the ASG32.
Associated pages, in alphabetical order.